Canon 400mm 5.6 with Kenko 1.4 PRO 300 DGX extender

I've had the Canon 400mm 5.6 lens for almost a year and love it. Recently I bought a Kenko 1.4 PRO 300 DGX extender to try with it. Had an opportunity to get some shots of eagles last weekend; looking at the scale on satellite photographs I was about 180-190 yards away. Of the 4 pictures I'm posting, the first three were taken with the extender, the last one wasn't. (Had to post the last one - don't think I'll ever get a shot like that again in the next 10 years.)

The extender works well with the 400...it autofocuses fine, displays the EXIF data correctly...images are good, although I seem to have a challenge with what appears to be camera movement when I take the shot...even on a tripod. Seems when I go to the 10 second timer, it gives the camera and lens a chance to "settle down" giving me clearer pics. Will try a remote shutter release soon.

The posted pics have been cropped to some extent and sharpened. I'm not saying these are the best images around - just wanted to post them so people can see what I'm getting with this lens/extender combination.

All in all, though...they could be worse. Suggestions for improving my images with this combination are certainly welcome!